Medulloblastoma

What it is

From: Orphanet

A rare embryonic tumor of the neuroepithelial tissue characterized clinically by increased intracranial pressure and cerebellar dysfunction, with the most common presenting symptoms being headache, vomiting, and ataxia. The disease can be classified according to histological (classic, anaplastic, large-cell, or desmoplatic medulloblastoma, or medulloblastoma with extensive nodularity) and molecular criteria (WNT-activated, sonic-hedgehog-activated, group 3, group 4).

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Medulloblastoma · Obligate (100%)

A rapidly growing embryonic tumor arising in the posterior part of the cerebellar vermis and neuroepithelial roof of the fourth ventricle in children. More rarely, medulloblastoma arises in the cerebellum in adults.

Abnormal brain FDG positron emission tomography · Frequent (79-30%)

An anomaly detectable in [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) brain scans. Glucose uptake measured with FDG-PET is a marker of neuronal metabolic activity.

Abnormal cranial nerve morphology · Frequent (79-30%)

Structural abnormality affecting one or more of the cranial nerves, which emerge directly from the brain stem.

Ataxia · Frequent (79-30%)

Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).

Cerebellar ataxia associated with quadrupedal gait · Frequent (79-30%)

The presence of cerebellar signs and symptoms such as lack of balance associated with quadrupedal gait (locomotion on all four extremities with a 'bear-like' gait with the legs held straight).

Delayed cranial suture closure · Frequent (79-30%)

Infants normally have two fontanels at birth, the diamond-shaped anterior fontanelle at the junction of the coronal and sagittal sutures, and the posterior fontanelle at the intersection of the occipital and parietal bones. The posterior fontanelle usually closes by the 8th week of life, and the anterior fontanel closes by the 18th month of life on average. This term applies if there is delay of closure of the fontanelles beyond the normal age.

Dysmetria · Frequent (79-30%)

A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements.

Headache · Frequent (79-30%)

Cephalgia, or pain sensed in various parts of the head, not confined to the area of distribution of any nerve.

Increased intracranial pressure · Frequent (79-30%)

An increase of the pressure inside the cranium (skull) and thereby in the brain tissue and cerebrospinal fluid.

Intention tremor · Frequent (79-30%)

A type of kinetic tremor that occurs during target directed movement is called intention tremor. That is, an oscillatory cerebellar ataxia that tends to be absent when the limbs are inactive and during the first part of voluntary movement but worsening as the movement continues and greater precision is required (e.g., in touching a target such as the patient's nose or a physician's finger).

Lethargy · Frequent (79-30%)

A state of fatigue, either physical or mental slowness and sluggishness, with difficulties in initiating or performing simple tasks. Distinguished from apathy which implies indifference and a lack of desire or interest in the task. A person with lethargy may have the desire, but not the energy to engage in personal or socially relevant tasks.

Nausea and vomiting · Frequent (79-30%)

Nausea is a commonly encountered symptom that has been defined as an unpleasant painless subjective feeling that one will imminently vomit. Vomiting has been defined as the forceful expulsion of the contents of the stomach, duodenum, or jejunum through the oral cavity. While nausea and vomiting are often thought to exist on a temporal continuum, this is not always the case. There are situations when severe nausea may be present without emesis and less frequently, when emesis may be present without preceding nausea.

Progressive macrocephaly · Frequent (79-30%)

The progressive development of an abnormally large skull.

Cerebellar medulloblastoma · Frequent (79-30%)

Other findings in the same source

From: Orphanet

Additional reported features include Progressive cerebellar ataxia (Frequent (79-30%)); Abnormality of bone marrow cell morphology (Occasional (29-5%)); Adenomatous colonic polyposis (Occasional (29-5%)); Back pain (Occasional (29-5%)); Bilateral sensorineural hearing impairment (Occasional (29-5%)); Cerebellar hemorrhage (Occasional (29-5%)); Cognitive impairment (Occasional (29-5%)); Diplopia (Occasional (29-5%)); Global developmental delay (Occasional (29-5%)); Hydrocephalus (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

All ages

Inheritance in the source

From: Orphanet

Not applicable

Frequency and the population described

From: Orphanet

Annual incidence: 1-9 / 1 000 000; Europe; Value and class. Point prevalence: 1-9 / 100 000; Europe; Value and class. Annual incidence: 1-9 / 1 000 000; United States; Value and class.

Which doctor should you see?

The suggested department for discussing Medulloblastoma is Oncology, with a oncologist and relevant organ specialist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Relevant organ specialist / Surgical Oncology as indicated.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Has the exact tumour type been confirmed, and is staging relevant?
• What is the goal of each proposed treatment option?
• How will side effects, daily function and supportive care be addressed?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Medulloblastoma. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.